Can you go on other forums(or here) and see if you can borrow a suit from someone or buy one used at a reduced price? For the spray tanning-I'm new, so take this with a grain of salt, but i've heard of people using the good stuff in the bottle and applying themselves with help from a hubby or the like, especially for the first "coat".
Perhaps find a hotel with an in room fridge and microwave and bring your own food so you don't have to pay to eat out while there?
Get your reservation for a hotel on hotels.com, orbitz or one of the discount websites.
Are there any incidentals you do daily or weekly you can drop to save up? (I know some people get Starbucks, their nails and hair done ALL. THE. TIME, etc) SO if you have fake nails or the like, go without them for the next 3 months or so and save like $60 on fills, etc. You can get a new set if needed before comp.

So I just found out that my sister may be moving in with me. I may not be able to financially handle going to a competition in April. It depends on how soon she gets a job and everything. Since I'm moving from bikini to figure, I'll need a new suit. Not to mention we know the spray tanning, the hotel, and incidentals pile up.

Anyone have any advice? Like a good place to order a suit at decent prices? I don't need to have Swarvski (sorry I butchered the spelling) crystals on it or anything.

I'm pretty disappointed, but she needs somewhere to go, she has a son who just turned one too. Can't just turn them away.

Divaexchange.com is great for used suits. Also, check suitsbyamy.com and check out her online store. She was many used, pre-made, and non-decorated suits on her site for sale at very low prices.